Hi,
On Tue, Dec 31, 2013 at 02:30:51AM +0000, Sergiusz Pawlowicz wrote:
> I think we still have some issues with cgroups. My server on 3.10x
> line started to freeze.
>
> After downgrading to 3.4x I am able to see one of vservers is rapidly
> leaking memory. It seems that probably cgroups on 3.10x kernel are not
> preventing from overfilling all RAM, without enforcing cgroup limits.
> The funny thing that vserver inside shows that memory is limited, but
> it seems it is not being enforced.
My experience is that memory limiting is enforced, but also for
kernel things like the ext4 filesystem and other things.
A vserver running out of memory that shares it's /vserver/ mount
with other vservers will effectively lock the ext4 system (making
it wait for memory within that memory cgroup), bringing down the
whole server until the vserver exceding it's memory usage gets
some more memory. These problems also seems to affect fusion-mpt
drivers. This behaviour is not easy to trigger: it takes a uwsgi
server 30 minutes to 24 hours of steady OOMing until it triggers
the ext4 lock-wait-for-memory at the right spot.
We have this kind of problems since the start of using memory
cgroups, but we never had any real problems with it. Usually the
OOMs made sure there were no real problems until people here
started to use python/uwsgi with memory leaks and such. The 3.10
series seems to be much faster lockable.
I think it is not vserver related, but just a bug in the vanilla
kernel memory cgroup system.
Regards,
Ard
Received on Tue Dec 31 14:38:02 2013